During sand casting, or stripping of the mold by means of a pressure water jet, there exists on the one hand the problem of providing a rational mode of operation and on the other hand achieving optimum economy with respect to the utilization of the auxiliary materials, namely, the sand and water. High-grade and, therefore, expensive sand is partly used. The water jet action requires much water, which cannot be discharged without first having been cleaned.
The goal of the invention is to increase the economy of sand molding and stripping by making the sand and water reusable, which practically results in a closed material cycle.
This is achieved in the above-mentioned method by inventively reclaiming both the sand and the water. If a special sand, for example quartz or zircon sand is used, to which is admixed a binding material, for example, cold resin or sodium silicate solution (water glass), then the method comprises
washing the entire form block by exposing same in a water jet enclosure to a high-pressure water jet, PA1 flushing out the muddy pulp and separating the green sand and water in a first water separator, PA1 guiding the green sand into a chamber having an agitator, in which the binding material which adheres to the sand is separated from the sand by rubbing the sand grains on one another, PA1 supplying the separated water to a water cleaning process for the sand to be used to make a new mold, PA1 the molding sand and water being ultimately separated in a second water separation and/or an oscillatory or rotating water separator or a filter press. PA1 to dry the sand, to cool it and supply it for reuse, and on the other hand PA1 to neutralize the water, possibly with the addition of CO.sub.2, supplied in the form of flue gas, PA1 to add to the water a flocculation agent, for example, ferric chloride, aluminum sulfate or the like or a flocculation auxiliary means, for example, a polyelectrolyte, and PA1 to clean it in a settling tank until it can again be used for loosening the sand in the jet housing. PA1 a hydro-jet housing, PA1 possibly a magnetic metal separator and a crusher for sand chunks, PA1 a first hydrocyclone for separating a large portion of the water from the muddy pulp, PA1 a rubbing mechanism for the sand, PA1 a washing container for the rubbed sand, PA1 a second hydrocyclone for separating a large portion of the water from the new muddy pulp, wherein from this hydrocyclone extends a return pipeline for the separated water to the washing container, PA1 a rotating or oscillatory water separator or a filter press, after which is connected a sand-drying and sand-cooling mechanism.
Expanding the method, it is possible on the one hand
To carry out the method, an apparatus is used which is inventively characterized by the series connection of
Thus, the reuse of sand and water is of a great advantage. The economical advantage can already be seen in a medium-sized installation using with a sand turnover of 10 t. sand and a water consumption of 8 m.sup.3, per hour .